Electrolytic cells are generally placed in commercial use for the production of chlorine, chlorates, chlorites, hydrochloric acid, hydrogen and other related chemicals, such as caustic solutions. Over the years, electrolytic diaphragm cells have undergone continuous development, e.g., improved operating efficiencies and improved lifetimes for cell components. This is often accomplished by continual design improvements.
Generally, such electrolytic diaphragm cells, and most particularly those designed to operate as chlor-alkali diaphragm cells, will contain a removable top which, upon removal, separates from a walled enclosure or shell. This enclosure, or shell, will typically rest upon a supportive cell base. The removable cell top, often a corrosion resistant plastic top, is seated at the top of the walled enclosure. At this juncture of the top with the walled enclosure, there is need for a tight seal by means of a sealing gasket. The same situation also exists at the juncture of the walled enclosure with the cell base.
For example, in U.S. Pat. No. 4,178,225, there is disclosed an electrolytic diaphragm cell and particularly such a cell operating as a chlor-alkali diaphragm cell. As disclosed in this patent, the cell contains the corrosion resistant plastic top, a cathode walled enclosure and a cell base. The cathode walled enclosure is positioned on the cell base and secured thereto by fastening means. The cathode top is positioned at the top of the walled enclosure and secured thereto by fastening means. The seal between the cell top and the cathode walled enclosure is maintained by means of a sealing gasket. Between the cell base and the walled enclosure, there is an elastomeric sealing pad.
As cell design improvements continue, individual cell components are providing longer and longer operating life. For some electrolytic diaphragm cells, the internal parts, e.g., the electrodes and the diaphragm, can now have a longer operating life than the cell sealing means. It is thus becoming of greater concern to provide a sealing means, such as between the cell top, or the cell base, or both, and the walled enclosure, that can achieve the long operating life of internal cell elements.